THE disgrace of Legislative Councillor Gilbert Leung Kam-ho raises questions not only about the social climate in which corruption such as his payment of ''tea-money'' to constituents is regarded as normal, but also about the electoral context in which it took place. As Mr Justice Keith put it, Leung has tarnished the integrity of the electoral process. The Regional Council functional constituency which Leung represents, boasts an electorate of just 36 people. In such a situation, a single vote can tip the balance and the temptation to buy support with a judicious ''donation'' of $50,000 or the replacement of an election agent's car with a new Mercedes-Benz will be very strong. The Regional Council is only the most rotten in a system which encourages ''rotten boroughs'', where tiny electorates of company directors or a few top ranking representatives can choose a legislator. That is why Governor Chris Patten has rightly talked about ensuring clean and fair elections. The political reform proposals, if they survive, will not only create nine new functional constituencies of 2.5 million electors, where tea money would be pointless, but also broaden the franchise in many of the existing seats and reduce the risk of corruption. Unfortunately, The Regional Council is an exception. Reform would boost the number of voters to only 39. In the longer term, it might be sensible either to abolish the seat altogether or broaden its base to avoid temptation. But there is also a broader significance to the Leung case, which makes the Independent Commission Against Corruption's determination to clamp down on tea money all the more important. As 1997 approaches, Hongkong must not become inured to the corruptionthat is endemic across the border. A moral fence must be built around the territory's democratic and public institutions to protect them from being undermined.